Piston



' 1,631,073 y 1927' c. soRENsoN PISTON Filed Jan. '7, 1927 Ti'azl.

Patented M8331, 1927' j UNITED STATES PATENT OFFICE.

cimi-s s'oannson, or TACOMA, wasnnveron.

I rrs'ron.

Application filed January 7, 1927. Serial 110. 159,719.

The primary object of my invention is to' provide an inexpensive self-adjusting piston of this'kind having a resilient skirt portion so split as to not unduly weaken the piston, but to permit sufiicient expansion and contraction as takes place from temperature changes under ordinary conditions of use so as to insure ordinary fitting of the pisto in its cylinder at all t1mes.' I

of the above kind which will be of such rigidity and construction as to have all of the advantages of a completelyrlgid piston, but to at the same time, have the added advantage of automatically keeping a snug fit in the cylinder in the presence of temperature changes. Another object is to provide a self-adjust,-

ing split-skirt piston, a maximum portionof the skirt of which is preserved in rigid form for providing a most eflicient bearing surface and at the same time insuring maximum strength and reliable support for the wrist pin bearing bosses.

Still another object is to provide a most practical means for insuring uniform expansion and contraction of "the flexible part of the skirt portion of the piston from end to.

end.

nature of the invention is better understood,

and the sameconsists in the novel form,

A combination and arrangement of parts hereinafter more fully described, shown in the accompanying drawing and claimed.

, In the drawing, wherein like reference characters indicate corresponding parts throughout the several views,

Figure 1 is an elevational viewof a piston constructed in accordance with my mv'ention' Y Figure 2 is a central longitudinal section *on line 22 of Figure 1;

Figure 3 is a central longitudinal section 0 on line 3-3 of Figure 2; and v Figure 4 is a transverse section on line 4-4 of Figure 2.

Referring more in detail to the drawing, the resent piston includes a hollow rigid head 5 having the usual annular packing ring receiving grooves 6. Extending in- A further ob]ect is to provide apiston- 'opposite sides of the bosses,

Other objects will become apparent as the wardly from and integral with the piston head 5 is the tubular skirt or body 7 which has the usual transverse opposed and in- Wardlyprojecting wrist pin bearing bosses 8.

The head 5 is reinforced byan internal rib 9 whichincludes a straight intermediate portion extending diametrically across th'e'inner face of the outer end wall of the head and opposed end portions which extend inwardly on the inner surface of the cylindrical wall of the headand join with the outer sides of the bosses 8 as at 10' so as to reinforce and lend effective support for the latter.

I As shown more clearly in Figure 2', the major'portion of the skirt is of a diameter slightly greater thanthat of the head and the latter. includes an annular reduced land 11 of uniform width at the inner side of the innermost groove 6. The portions of-the skirt surrounding the bosses 8 are externally reduced fr-om the land 11 inwardly to a point slightly beyond said bosses as at- 12 to provide relief areas 13 that are eccentric to the skirt and merge with the outer sur-' face of the latter as at 14 adjacent to and at This leaves tapering shoulders 15 at the inner sides of the adjacent portionsof land 11 narrower than the shoulders formed at 12.

A circumferentiall extending slot 16 partly severe .thehea from the skirt at the inner side of the land 11, and this slot extends for' approximately degrees of the circumference of the piston, starting at a point l6 midway between the bosses 8 and- ,extending to the nearest adjacent point 14 where one of the relief areas 13' merge with the normal portion ofthe skirt. Further, theskirt is divided longitudinally by means of an inclined or oblique slot 17 whose slant is approximately 7 degrees and which extends from the end of the slot 16 which is nearest a boss,8 to the inner end of the skirt and in a direction away from this boss.

This renders the skirt approximately 60 degree's resilient and 300 degrees rigid or solid, and defines a resilient flexible skirt. part 18 bounded on two sides by the slots.

Approximately midway between the ends of the skirt 7 the latter is provided with a circumferentially extending internal rib 19 which extends on the part 18 from apoint about midway between the ends ofslot 16 away from slot 17 to the boss 8 farthest from the slot 17, This rib 19 prevents the flexible part 18 of the skirt from caving in skirt,

From the above, it Will be seen that I have provided a piston which is about 300 degrees side of the skirt part rigid and which provides this amount of the body for support of the wrist pin bearing bosses. In view of this fact, the piston -w1ll .not readily cave in or become distorted in service by close fitting, as is experienced with priorconstructions in which the skirt portion is severed to a much greater degree or extent from the head. Moreover, objectionable stifitening struts between the sides of the bearing bosses and the skirt are rendered unnecessary, and the possibility of cylinder scoring is minimized. V

Minor changes may be made without departing from the spirit and scope of the invention as claimed.

It is noted that the present piston is quite efiicient without the provision of the relief areas 13 and-they may accordingly be eliminated without departing from the spirit of the invention.

What I claim as new is 1. A piston having a head, a skirt, and wrist pin bearin bosses, the head on both sides of one of t e bearing bosses and one side of the other'bearing boss being integral with the skirt, the skirt being separated from the head at the other side of said other bearing boss by a circumferentially extending slot and being divided by a longitudinal slot communicating with said circumferentially extending slot, thereb rendering the slotted y resilient, and means to distribute the tension on the resilient skirt part uniformly from end to end of the latter, said last named means embodying a circumferentially extending rib formed internallyv of the skirt and extending partly across said resilient part of the skirt.

2. A piston having a head, a skirt, and Wrist pin bearing bosses, the head on both sides of one of the bearing bosses and one side of the other bearing boss being integral with the skirt, the skirt being separated from the head at the other side of said other bearing boss by a circumferentially extending slot and being divided by a longitudinal slot communicating with said circumferentially extending slot, thereby rendering'the slotted side of the skirt partly resilient, and means to distribute the tension on the resilient skirt part uniformly from end to end of the latter, said last named means embodying a. circumferentially extending rib formed internally of the skirt andextending partly across said resilient part of the sklrt, said rib being located between the ends of the skirt, and a divided fillet extending. entirely around the inner end of the skirt.

3. A piston having a head, a skirt, and Wrist pin bearing bosses, the head on both sides of one of the bearing bosses and one side of the other bearing boss being integral with the skirt, the skirt being separated from the head at the other side of saidother bearing boss by a circumferentially extending slot and being divided by a longitudinal slot communicating with said circumferentially extending slot, thereby rendering the slotted side of the skirt partly resilient, there being a relieved peripheral area about the end of each bearing boss, and said circumferentially extending "slot extending from a point midway between the beari'ng bosses to the adjacent side of one of said relieved areas. I

4. A piston having a head, a skirt, and

wrist pin bearing bosses, the head on both sides of one of the bearing bosses and one side of the other bearin boss being integral with-the skirt, the skirt being separated from the head at the other side of said other bearing boss by a circumferentially extending slot and being divided by a longitudinal slot communicating with said circumferentially extending slot, thereby rendering the slotted side of the skirt partly resilient, there being a relieved peripheral area about the end of each bearing boss, and said circumferentially extending slot extending from a point midway between the bearing bosses to the adjacent side of one of said relieved areas, said longitudinal skirt from the end of the circumferential slot terminating at said relieved area toward but. short of the longitudinal plane of the piston at which the other end of said circumferential slot terminates.

5. A piston having a head, a skirt, and wrist pin bearing bosses, the head on both sides of one of the bearing bosses and one side of the other. bearing boss being integral with the skirt, the skirt'bein separated from the head at the other side of said other hearing boss by a circumferentially extending slot'and being divided by a longitudinal slot communicating with said circumferentially extending slot, thereby rendering the slotted side of the skirt partly resilient, said circumferential slot extendin for approximately sixty degrees of the circumference of the skirt, and said longitudinal slot extending obliquely at an angle of approximately seven degrees from the end of the circumferential slot which is nearest said other bearing boss toward the longitudinal plane of the piston at which the other end of the circumferential slot terminates. Y

slot extending obliquely of the In testimony whereof I afiix my signature.

CHRIS SOREN SON 

